1. Field of Invention
The present invention relates to a LED indicator for producing a light bar in a bargraph, in particular for an instrument on a motor vehicle.
2. Description of the Related Art
In the instrument panel of motor vehicles, as an alternative to common pointer indicators, it is known in the art to use so-called bargraphs, which are backlit by a row of LEDs to produce a light bar of variable length. The length depends on the number of adjacent LEDs that are switched on and provides visual information of a variable quantity, in particular of a measurement carried out in the motor vehicle (e.g. the measurement of speed, engine RPM, fuel consumption, etc.).
LEDs are usually housed in respective cavities, which are separated from one another by screens. In solutions known in the art, such screens extend orthogonally to the bargraph, up to the lower surface of the bargraph itself, so as to prevent any leakage of light towards the adjacent cavities where the LEDs are off. Due to this configuration, the backlighting of the bargraph produces a series of segments, which are arranged between areas turned off or with dim light due to the presence of the underlying screens. With this configuration, the reading of the measured value on the bargraph is well defined due to the absence of leakages of light from the lighted segments to the dark ones. An example of this kind of solution is shown in published U.S. Pat. No. 5,949,346A.
However, if obtaining a bar of continuous, non segmented light is desired, it would be appropriate to reduce the height and/or thickness of the screens. Further, by operating in this manner with the known solutions, there would be a leaking of light from the last cavity having a switched on led towards the dark side of the bargraph, whereby the visual indication of the measurement would not be accurately perceived by the user.